Use

This plugin provides the MTValidate container tag.
The contents of this tag should be a complete HTML, XHTML, SGML or XML
document, which will be replaced with the results of the validation.
There are also several attributes you can provide. Set their value to
“1” to enable, “0” to disable:

verbose
Verbose output (on by default): If this is disabled, the other
options will be ignored.

ss
Displays the HTML source of the document you validated and links
error messages directly to lines in this output. Makes it easy to see
what’s wrong. The source is always shown if there is an error.

outline
Will generate an outline of your document from the H1 - H6
elements. For a properly formed document, this will be a nicely nested
tree structure. The visualization of your document’s structure makes
it easier to see where you’ve skipped a heading.

sp
Shows you exactly how the SGML Parser read your
document. Probably best used only by advanced users as it deals with
low-level SGML constructs.

noattr
Suppress attributes from the parse tree to make it more readable.

charset
The character set of the document to be validated. For example,
utf-8 or iso-8859-1. If not specified, the
validator will try to guess based on the HTML META
element or XML declaration.

doctype
The document type to apply to the document. Normally, this is
extracted from the DOCTYPE declaration in the document
itself, but you
can override it using this attribute. For example,
HTML 3.2 or XHTML 1.0 Transitional

Here is an example that validates the title and body of an entry,
based on the default
templates from Movable Type 2.51: